Needle protective device

ABSTRACT

A needle protective device has a tubular member (14) with an end cap (16). One end (12) of the member (10) engages on needle hub (22), and the other end has a cap (16) with an opening (34). The tubular member is flexible and has cut-outs (18) in its wall. Normally the needle (26) is directed away from the opening 34) so that the needle tip is enclosed by the cap (16). To use the needle, the end cap (16) is displaced to bring the needle alongside guide ribs (38) and the tubular member (14) compressed axially to expose the needle (26) through the opening (34).

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No.08/211,365 filed 5 Jul. 1994, now U.S. Pat. No. 5,538,508.

BACKGROUND TO THE INVENTION

This invention relates to a protective device for a needle of a syringe,catheter or similar medical appliance for human or animal use.

Various protective devices of this kind are known for an elongate needleof the aforementioned kind having a base at one end and a point at anopposing end which devices include a blocking surface and means whichextends from the base and which supports the blocking surface, theblocking surface having a hole and being movable at least towards thebase to allow the needle to extend through the hole. However these havegenerally suffered from the disadvantage of being relatively expensivein a field where low cost is of the greatest priority due to the largevolume required.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a novel inexpensiveand effective protective device of the kind described.

The invention provides a needle protective device for a needle assemblyhaving a needle hub and a needle projecting from the hub, the needleprotective device comprising, a tubular member of resilient flexiblematerial which extends about the needle, the tubular member having firstand second ends, a first end of the tubular member having a bevelthereon and being mounted skew on and frictionally engaged with theneedle hub with the bevel normal to the longitudinal axis of the needlehub, and an end cap mounted on the second end of the tubular member, theend cap having a blocking surface defining a hole through which an endof the needle may pass, the skew mounting biasing the tubular member toa position in which the end of the needle opposes the blocking surface.

Preferably a plurality of cut-outs are provided in the wall of thetubular member extending in the axial direction between the first andsecond ends. These cut-outs which are preferably in the form of slitsand diametrically opposed to each other.

According to a further preferred feature of the invention the slitsterminate at either end in round holes. These holes are advantageous inthat they prevent the slits from tearing.

While not essential it is preferred that at least one gripping means isprovided on the exterior of the tubular member. The provision of thegripping means enables the tubular member to be gripped for stretchingover the needle hub and the end cap during assembly.

The gripping means may take various forms. In one form, the grippingmeans consists of a flange on the tubular member at or adjacent eachend. In another form the gripping means includes a plurality offormations disposed about the circumference of the tubular member. Theseformations may be in the form of lugs or alternatively in the form ofribs extending over at least a substantial portion of the length of thetubular member.

When the gripping means is in rib form it serves a further purpose ofstiffening the tubular member.

In addition the tubular member may have protruding laterally therefromat or adjacent each end a registration tab. This tab is used to locateand orientate the end cap in the vibrating bowls used to feed the endcaps during an automated process for assembling them onto the tubularmembers.

The end cap may include a chamber which is open at one end which isattached to the said second end of the tubular member, the blockingsurface being located at an opposing end of the chamber, with a passagebeing formed inside the chamber leading to the opening.

The end cap may internally also be provided with one or more formationsadapted to guide the needle point to the mouth of the passage when theneedle is displaced sideways within the end cap.

The tubular member may be made from a transparent material but couldalternatively be made from an opaque coloured material.

The end cap is preferably made from a transparent material so that atleast the point of the needle is visible.

The tubular member is preferably made from silicone rubber. It has beenfound that the tubular member can be made in a normal rubber injectionmoulding process using medical grade liquid silicone rubber. Thesilicone rubber preferably has a Shore hardness of approximately 30-80.

Less preferably the tubular member can be made from thermoplastic rubberor thin walled rubber.

The tubular member may be injection moulded or extruded, with anextrusion process being preferred because of its cost effectiveness.

The end cap is preferably made in a plastic injection moulding processusing medical grade clear polystyrene. This ensures transparencycompared for example to the use of polyethylene which results in a milkyor cloudy product.

The passage in the end cap is preferably offset so that a wall of thepassage and the blocking surface create a recessed formation whichreceives the needle point.

The passage is preferably flared and increases in cross sectionaldimensions from its end inside the chamber to the opening at theblocking surface. This minimizes the likelihood that the point of theneedle can become snagged on the wall of the passage and, in turn,reduces the likelihood that the point of the needle can thereby becomedamaged.

The silicone rubber used in the tubular member can withstand gamma orother radiation for sterilization purposes. The rubber is also stable upto a temperature of at least 200 deg.C and is ultraviolet resistant to asubstantial extent.

The tubular member is preferably frictionally engaged with a hub of theneedle at the first end and is frictionally engageable with the end capat the second end. The end cap may include an external flange whichassists in correctly locating the second end of the tubular member onthe end cap.

The rim or flange also reinforces the chamber.

The end cap preferably has a relatively substantial axial dimension i.e.in the axial direction of the needle. Consequently when the tubularmember is fully compressed a fairly substantial portion of the length ofthe needle is inside the tubular member. This acts as a safety featurefor, if the needle does break while an injection is being given, it willin all probability break, not at the hub of the needle but inside thechamber. The needle will therefore be easier to extricate from apatient.

According to a still further feature of the invention the tubular memberhas internally between its ends areas of weakness which predispose thetubular member to bow laterally outwardly on axial compression. Theseareas of weakness may suitably be provided by notches in the edges ofthe slits.

The invention also extends to a combination of needle protective deviceand needle assembly, which comprises a needle assembly, including a huband a needle projecting from the hub and the needle protective device ofthis invention engaged to the hub.

According to a preferred feature of the invention in which the axis ofthe needle is skewed relative to the longitudinal member of the tubularmember to a position opposite the blocking position.

In one form of the invention the first end of the tubular member isnormal to the longitudinal axis of the tubular member and is mounted onthe needle hub skew to such normal.

In another embodiment of the invention, the first end of the tubularmember is provided with a bevel and the tubular member is mounted on theneedle hub with the bevel normal to the longitudinal axis of the needlehub.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings which illustrate by way of examplepreferred embodiments of the invention:

FIG. 1 is a plan view of a needle protective device and needle assemblyaccording to one embodiment of the invention,

FIG. 2 is a longitudinal section of FIG. 1,

FIG. 3 is a perspective view of the tubular member of FIG. 1,

FIGS. 4 and 5 are similar view of further embodiments of the tubularmember,

FIG. 6 is a section along the line 6--6 of FIG. 2.

FIG. 7 is a side elevation of the tubular member of FIG. 3 of a secondembodiment of the invention,

FIG. 8 is a plan view of the needle protective device and needleassembly according to FIG. 7 of the embodiment of the invention, and

FIG. 9 is a longitudinal section of FIG. 8.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 of the accompanying drawings illustrate a needleprotective device 10 according to the invention, and a needle assembly12. The needle protective device includes a tubular member 14 and an endcap 16.

The tubular member 14 is made either from medical grade liquid orstandard silicone rubber with a Shore hardness of 30 to 80 in aninjection moulding or extrusion process. The silicone rubber ispreferably transparent, but may be colour coded to indicate needledimensions. Standard silicone rubber (i.e. in paste form) can be usedfor the extrusion process, whereas liquid silicone rubber can be usedfor both the extrusion and injection moulding process.

The tubular member 14 is in the form of a cylinder of substantiallyconstant cross section having axially extending slits 18 therein. Theslits 18 terminate at either end in round holes 20 to prevent the slits18 from tearing.

The needle assembly 12 is conventional and includes a hub 22 with an endrim 24 and an elongate steel needle 26 extending from the hub.

The end cap 16 is injection moulded from medical grade clearpolystyrene. As more clearly shown in FIG. 2 the end cap 16 defines aninner chamber 28, a sloping blocking surface 30 and a flared passage 32extends to an opening 34 in the blocking surface 30. A flange 36 extendsaround an outer surface of the chamber 28. The flared passage 32minimises the likelihood of the needle point snagging on the passagewalls. Snagging can be even further minimised by providing a cut-away 37in the wall of the passage 32. The inner wall of the chamber 28 is alsoformed with one or more guide ribs 38 which serve to guide the needlepoint into alignment with the mouth 40 of the flared passage 32, whenthe needle point is displaced sidewardly. The ribs 38 may also divergerearwardly away from each other to facilitate guidance of the needlepoint.

The liquid silicone tubular member is frictionally engaged with the hubof the needle 26 and with the end cap, by stretching the ends of thetubular member 14 over the hub and end cap. It will be noted withreference to FIG. 2 that the end of the tubular member 14 is normal toit longitudinal axis and that the positioning of the end of the tubularmember 14 on the needle hub 22 is skewed relative to the longitudinalaxis of the hub 22, so that the needle will normally be disposed to lieadjacent the wall of the chamber 28 opposite to the location of theflared passage 32. The skewing is indicated by the gap 41 between theend of the tubular member 14 and the end rim 24 of the needle hub 22.

The sloping blocking surface 30 is provided to facilitate theadministering of an intravenous injection where the needle is requiredto enter the patient at an angle.

For intravenous injection needles the tubular member 14 can be mountedon the needle hub 22 in such a way that the bevel on the needle pointslopes in the same direction as the sloping blocking surface 30. Thusthe operator simply by viewing the sloping blocking surface 30 will knowthat the bevel of the needle is in the correct disposition relative tothe patients skin. It is not necessary to visually inspect the needlepoint itself to ensure this result.

The wall 42 of the passage 32 and the sloping blocking surface 30 definea safety chamber 44 for the point of the needle. It will be noted thatthe point of the needle is in alignment with the rear end of the wall 42of the passage and thus by displacing the safety chamber 44 to one side,the needle can be aligned with the passage 32 for the injectionprocedure.

The tubular member 14 has a section of circumferentially disposed axialribs 46 extend over it length. The ribs 46 enable the tubular member tobe gripped at its ends when such ends are to be stretched over theneedle hub and the end cap during assembly. These ribs 46 areparticularly useful in an automated assembly process when they can bereleasably engaged with suitable mechanical devices such as clamps tofacilitate the required stretching of the tubular member. The ribs 46also serve to stiffen the tubular member 14.

The ribs 46 can be moulded onto the tubular member 14 in an injectionmoulding process, but most conveniently can be formed in an extrusionmoulding process which is the more cost effective of the two processes.

A tab 48 can be formed on the flange 36 to assist in orientation andlocation of the end cap 16 in the vibrating feed bowls used in anautomated assembly process for fitting the tubular member onto the endcap and needle hub.

Finally it will be seen that along the edges of the axial slits 18 inthe tubular member 14, notches 50 are provided. These notches 50 ensurethat when the tubular member 14 is axially compressed it will bedisposed to bow outwardly enabling the end cap 16 to be retracted untilit encounters the needle hub 22.

FIG. 4 shows an injection moulded tubular member 14 with gripping meansin the form of a radial flange 52 at either end. In FIG. 5 the ribs 46on the tubular member 14 are replaced by lugs 54 adjacent either end ofthe tubular member 14.

It will be noted that the ribs 46 and the lugs 54 extend radially beyondthe portion of the wall of the tubular member between adjacent ribs 46and lugs 54. This stabilises the tubular member 14 against rolling inuse or during the assembly process.

In use, the needle 26 being normally disposed in the position shown inFIG. 2 lies opposite the blocking surface 30 and therefore it isvirtually impossible for the needle to inadvertently enter the flaredpassage 32. The needle 26 is constrained to such a disposition due tothe resilience of the material from which the tubular member 14 is madein combination with the skewed relation of the tubular member 14 and theneedle hub 22. When it is desired to extend the needle 26 through thepassage 32, the safety chamber 44 is displaced sideways bringing theneedle 26 in contact with one of the guide ribs 38 which automaticallyguides the needle point into alignment with flared passage 32.

In order to administer an injection, with the needle hub 22 fitted tothe nozzle of a syringe, the needle is aligned with the passage 32 andthe tubular member 14 is axially compressed to extend the needle throughthe passage 32. With the needle thus exposed the point of the needle isinserted into the patients skin and the tubular member 14 released toresile forward until the blocking surface 30 lies against the skin ofthe patient. At the end of the injection procedure as the needle iswithdrawn from the patient the tubular member 14 axially expands causingthe needle to be retracted through the passage 32 into the tubularmember 14 with the needle point opposite the blocking surface 30.

Referring to FIGS. 7, 8 and 9 there is shown an embodiment of theinvention in which the tubular member 14 is provided with a bevel 56 atthe end which is engageable with the hub 22. As will be noted the bevelend is flush against the end rim 24 of the needle hub 22 which has theeffect of skewing the tubular member 14 on the needle hub 22 therebyresiliently biasing the needle 28 to a position opposite the blockingsurface 30. It will be realised that a bevelled end may also be providedon the tubular member 14 in FIGS. 4 and 5 with a similar result.

It will be noted further with reference to FIG. 9 that the needle point28 in this embodiment is disposed with the bevel on the needle point inan opposite direction to the bevel on the sloping blocking surface 30.This means that the point is distal from the outer wall of the passage32, thus when the needle is protruded through the passage, snagging isvirtually eliminated and the cut-out 37 can be dispensed with. Thehandling of the device during the handling procedure is greatlysimplified. It will be noted that the bevel of the protruded needle isautomatically in the correct position relative to the patients skin.

It should be realised that while the sloping blocking surface 30 isincluded in the illustrated embodiments because it facilitates insertionof the needle, this is not essential, and the end of the end cap mayalso be squared off.

I claim:
 1. A needle protective device for a needle assembly having aneedle hub and a needle projecting from the hub, the needle protectivedevice comprising, a tubular member of resilient flexible material whichextends about the needle, the tubular member having first and secondends, a first end of the tubular member having a bevel thereon and beingmounted skew on and frictionally engaged with the needle hub with thebevel normal to the longitudinal axis of the needle hub, and an end capmounted on the second end of the tubular member, the end cap having ablocking surface defining a hole through which the end of a needle maypass, the skew mounting biasing the tubular member to a position inwhich the end of the needle opposes the blocking surface.
 2. The needleprotective device of claim 1, in which the end cap defines a chamberwhich is open at one end, the end cap being attached at the one end tothe second end of the tubular member, the blocking surface beingdisposed opposite the open end of the chamber; anda passage, provided inthe chamber, leading to the hole in the blocking surface.
 3. The needleprotective device of claim 2, in which the end cap includes one or moreformations adapted to guide the end of the needle towards a mouth of thepassage when the end of the needle is displaced sideways towards thepassage.
 4. The needle protective device of claim 3, in which thepassage flares outwardly from the hole towards the mouth.
 5. The needleprotective device of claim 2, in which the passage is offset to one sideof the end cap.
 6. The needle protective device of claim 1, in which theend of the needle is beveled and the blocking surface slopes in the samedirection as the bevel.
 7. The needle protective device of claim 1 inwhich a plurality of slits is provided in a wall of the tubular member,the slits extending in an axial direction between the first and secondends.
 8. The needle protective device of claim 7, in which notches areformed in edges of the slits to predispose portions of the wall of thetubular member to bow outwardly when the first and second ends are urgedtogether in the axial direction.
 9. The needle protective device ofclaim 1, in which the end cap is of transparent material.
 10. The needleprotective device of claim 2, in which the passage is defined in part bya portion of an outer wall of the end cap, a cut out being provided inthe outer wall portion and extending from a junction of the wall portionwith the blocking surface.
 11. The needle protective device of claim 1,in which an external flange is provided on the end cap.
 12. The needleprotective device of claim 11 including at least one gripping means onan exterior surface of the tubular member.
 13. The needle protectivedevice of claim 12 in which the gripping means includes a flange at oradjacent the first or second end of the tubular member.
 14. The needleprotective device of claim 12 in which the gripping means includes aplurality of lugs disposed about a circumference of the tubular member.15. The needle protective device of claim 12 in which the gripping meansincludes one or more ribs extending along an outer surface of thetubular member.
 16. The needle protective device of claim 12 in which aregistration tab is provided on the end cap and protrudes laterallytherefrom.
 17. The needle protective device of claim 14 in which thereare at least two ribs which protrude laterally beyond the portion of thewall of the tubular member between adjacent ribs.
 18. The needleprotective device of claim 15 in which the lugs protrude radially beyondthe portion of the wall of the tubular member between adjacent lugs. 19.The combination of a needle protective device and a needle assembly: theneedle assembly comprising a hub and a needle projecting from the hub,the needle protective device comprising a tubular member of resilientflexible material which extends about the needle, the tubular memberhaving first and second ends a first end of the tubular member beingmounted on and frictionally engaged with the needle hub, and an end caphaving a blocking surface, the blocking surface defining a hole throughwhich the end of a needle may pass, wherein the first end of the tubularmember is mounted skew on the hub to bias the tubular member to aposition in which the needle opposes the blocking surface.
 20. Thecombination of claim 19 in which the first end of the tubular member hasa bevel thereon and is mounted with the bevel normal to the longitudinalaxis of the needle hub.
 21. The combination of claim 20, in which theend cap defines a chamber which is open at one end, the end cap beingattached at one end to the second end of the tubular member, theblocking surface being disposed opposite the open end of the chamber,and a passage, provided in the chamber, leading to the hole in theblocking surface.
 22. The combination of claim 21, in which the end capincludes one or more formations adapted to guide the end of the needletowards a mouth of the passage when the end of the needle is displacedsideways towards the passage.
 23. The combination of claim 22, in whichthe passage flares outwardly from the hole towards the mouth.
 24. Thecombination of claim 21, in which the passage is off set to one side ofthe end cap.
 25. The combination of claim 19 in which the end of theneedle is bevelled, and the blocking surface slopes in the oppositedirection to the bevel.
 26. The combination of claim 19 in which aplurality of slits is provided in a wall of the tubular member, theslits extending in an axial direction between the first and second ends.27. The combination of claim 26 in which notches are formed in the edgesof the slits to predispose the wall portions of the tubular member tobow outwardly when the first and second ends are urged together in theaxial direction.
 28. The combination of claim 19 in which the end cap isof transparent material.
 29. The combination of claim 20 in which thepassage is defined in part by a portion of the outer wall of the endcap, and a cut out is provided in the outer wall portion and extendingfrom a junction of the wall portion with the blocking surface.
 30. Thecombination of claim 19 in which an external flange is provided on theend cap.
 31. The combination of claim 19 including gripping means on anexterior surface of the tubular member.
 32. The combination of claim 31in which said gripping means includes a flange at or adjacent the firstor second end of the tubular member.
 33. The combination of claim 31 inwhich said gripping means includes a plurality of lugs disposed aboutthe circumference of the tubular member.
 34. The combination of claim 31in which the gripping means includes one or more ribs extending along anouter surface of the tubular member.
 35. The combination of claim 31 inwhich a registration tab is provided on the end cap and protrudeslaterally therefrom.
 36. The combination of claim 34 in which there area plurality of ribs which protrude laterally beyond the portion of thewall of the tubular member between adjacent ribs.
 37. The combination ofclaim 33 in the lugs protrude radially beyond the portion of the wall ofthe tubular member between adjacent lugs.